JP5673569B2 - Insulated wire - Google Patents

Description

The present invention relates to an insulated wire using a soft vinyl chloride resin composition having both electrical insulation and low-temperature resistance and thermal aging resistance.

  Vinyl chloride resin (polyvinyl chloride) is a typical halogen-containing resin used as a wire covering material because it exhibits excellent water resistance and chemical resistance, and further exhibits electrical insulation and flame resistance. In the case of using a vinyl chloride resin, a phthalate ester or trimellitic acid ester has generally been added as a plasticizer.

  For example, Patent Document 1 (JP-A-8-34891) discloses 2-propylheptanol or a mixture of 2-propylheptanol and 4-methyl-2-propylhexanol as a plasticizer, A vinyl chloride-based resin composition using a phthalate ester having a methyl-2-propylhexanol content of 30% by weight or less is disclosed. According to Patent Document 1, a semi-rigid vinyl chloride resin composition having improved processability and cold resistance can be provided.

  On the other hand, in recent years, there is a strong desire to protect the global environment and human health worldwide, and the use of safer materials is strongly desired in the industrial world. For example, in the European Union (EU), the Regulation on the Restriction of Use of Certain Hazardous Substances in Chemicals (REACH Regulation) was enforced on June 1, 2008. Some of the phthalates are designated as SVHC (substance of very high concern) by the REACH regulation, and plasticizers that contain them are incapable of complying with the REACH regulation.

  A vinyl chloride resin composition to which a plasticizer not containing a phthalate ester is added is proposed in, for example, Patent Document 2 (Japanese Patent Laid-Open No. 7-211153). Patent Document 2 discloses 2-propylheptanol or a mixture of 2-propylheptanol as a plasticizer and 4-methyl-2-propylhexanol, and the content of 4-methyl-2-propylhexanol is 30. There is disclosed a vinyl chloride resin composition for electric wire coating using a triester of trimellitic acid and those having a weight% or less. According to Patent Document 2, it is said that a vinyl chloride resin composition for electric wire coating having low volatility and good properties such as plasticization efficiency, cold resistance, and heat aging resistance can be provided.

Japanese Patent Laid-Open No. 8-034891 Japanese Patent Application Laid-Open No. 7-2111153

  The vinyl chloride resin composition for electric wire coating described in Patent Document 2 is expected to have good characteristics in electrical insulation, cold resistance, and heat aging resistance, but is a relatively expensive compound as a plasticizer. Because of the use of the material, the material cost tends to be high, and there is a problem that it is difficult to meet the demand for cost reduction.

Therefore, an object of the present invention is to satisfy the above requirements by having an insulating coating made of a soft vinyl chloride resin composition that does not contain a phthalate ester and has good electrical insulation, cold resistance, and heat aging resistance. It is to provide an insulated wire at a low cost .

(I) According to one aspect of the present invention, an insulated wire having an insulation coating on the outer periphery of a metal conductor wire, wherein the insulation coating is a soft vinyl chloride resin composition obtained by adding a plasticizer to a vinyl chloride resin. The plasticizer is a mixture of a first plasticizer made of trimellitic acid ester and a second plasticizer made of cyclohexanedicarboxylic acid ester, the first plasticizer (A) and the second plasticizer. The mass ratio (A / B) to (B) is 4/96 or more and 96/4 or less, and the total amount (A + B) of the first plasticizer (A) and the second plasticizer (B) is the 80 parts by der than 40 parts by weight or more with respect to 100 parts by weight of vinyl chloride resin is, the soft quality vinyl chloride resin composition having an electrical insulation property volume resistivity is 10 ¹³ Ω · cm or more under a 60 ° C. atmosphere Provided is an insulated wire made of a material.

Furthermore, the present invention can add the following improvements and changes to the above-described insulated wire according to the present invention.
(I) The first alkyl group ester-bonded to the first plasticizer and the second alkyl group ester-bonded to the second plasticizer both have 8 to 10 carbon atoms .

According to the present invention, it is possible to provide an insulated wire having an insulating coating made of a soft vinyl chloride resin composition that does not contain a phthalate ester and has good electrical insulation, cold resistance, and heat aging resistance at low cost. Can do .

It is a cross-sectional schematic diagram which shows one example of the insulated wire which concerns on this invention.

  Embodiments according to the present invention will be described below. However, the present invention is not limited to the embodiment taken up here, and can be appropriately combined and improved without departing from the scope of the invention.

[Soft vinyl chloride resin composition]
As described above, the soft vinyl chloride resin composition used in the present invention is characterized by a plasticizer added to the vinyl chloride resin. The plasticizer is a mixture of a first plasticizer (A) made of trimellitic acid ester and a second plasticizer (B) made of cyclohexanedicarboxylic acid ester.

  The trimellitic acid ester and cyclohexanedicarboxylic acid ester used in the present invention are represented by the following general chemical formulas (1) and (2), respectively. In the present invention, R in the chemical formula represents an alkyl group having 8 to 10 carbon atoms.

  Examples of trimellitic acid ester of chemical formula (1) used in the present invention include tri-2-ethylhexyl trimellitic acid (TOTM), triisononyl trimellitic acid (TINTM), and triisodecyl trimellitic acid (TIDTM). . Examples of the cyclohexanedicarboxylic acid ester of the formula (2) used in the present invention include, for example, 1,2-cyclohexanedicarboxylic acid di-2-ethylhexyl (DOCH), 1,2-cyclohexanedicarboxylic acid diisononyl (DINCH), 1 , 2-cyclohexanedicarboxylate diisodecyl (DIDCH) and the like.

  The addition of trimellitic acid ester (that is, the addition of the first plasticizer) has a high effect of improving the electrical insulation properties of the vinyl chloride resin composition, but tends to decrease the cold resistance. This is because, as shown in chemical formula (1), trimellitic ester has a benzene ring and high polarizability, and therefore has a strong interaction with the vinyl chloride resin, which is a polar polymer, and a strong binding force. In other words, the higher the intermolecular bond, the lower the flexibility and the lower the cold resistance, but the movement of carriers (for example, ionic impurities and metal ions generated by dehydrochlorination trapping) in the plasticizer. Therefore, electrical insulation is improved.

  Moreover, addition of trimellitic acid ester contributes to the improvement of the heat aging resistance of the vinyl chloride resin composition. This is because the volatilization amount of the plasticizer during heating is small. In the present invention, trimellitic acid ester has a higher molecular weight than cyclohexanedicarboxylic acid ester. For this reason, the van der Waals force acting between the molecules becomes strong and the boiling point becomes high, so that it is difficult to volatilize.

  On the other hand, the addition of cyclohexanedicarboxylic acid ester (that is, the addition of the second plasticizer) has a high effect of improving cold resistance, but tends to lower the electrical insulation. This is because, as shown in chemical formula (2), cyclohexanedicarboxylic acid ester has few polar parts in its molecular structure (because it does not have a benzene ring), and therefore the interaction with vinyl chloride resin is weak and the binding force is also weak. to cause. In other words, since the bonding property between molecules is low, flexibility is improved and cold resistance is improved. On the other hand, the effect of restricting the movement of carriers in the plasticizer is small, and the molecular motion becomes active as the temperature rises, so that the electrical insulation is lowered.

  The mass ratio (A / B) of the first plasticizer (A) made of trimellitic acid ester and the second plasticizer (B) made of cyclohexanedicarboxylic acid ester is 4/96 or more and 96/4 or less. Is preferred. By setting the mass ratio (A / B) to “4/96 ≦ A / B ≦ 96/4”, all the electrical insulation, cold resistance and heat aging resistance of the soft vinyl chloride resin composition are improved in a well-balanced manner. Can be made.

  The total addition amount of the first plasticizer and the second plasticizer is preferably 40 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin. When the total addition amount is less than 40 parts by mass, sufficient flexibility cannot be obtained, and cold resistance and heat aging resistance are insufficient. On the other hand, if the total addition amount exceeds 80 parts by mass, the electrical insulation is insufficient.

  In addition to the basic effects resulting from the bond between the vinyl chloride resin and the plasticizer, the electrical insulation and cold resistance characteristics of the soft vinyl chloride resin are strongly influenced by the carbon number of the alkyl group in the plasticizer molecule. . Specifically, a soft vinyl chloride resin to which a plasticizer having a large number of carbon atoms in an alkyl group is added exhibits good cold resistance, but its electrical insulation is reduced. In contrast, a soft vinyl chloride resin to which a plasticizer having a small number of carbon atoms in an alkyl group is added exhibits good electrical insulation, although the cold resistance is lowered.

  The first alkyl group ester-bonded to the first plasticizer and the second alkyl group ester-bonded to the second plasticizer both have 8 to 10 carbon atoms (C8 to C10). Is preferably 8 or more and 9 or less (C8 or more and C9 or less). When the alkyl group is C7 or less, sufficient heat resistance required for the insulation coating cannot be secured. This is because the shorter the alkyl group (that is, the smaller the number of carbon atoms and the smaller the molecular weight), the more easily the plasticizer volatilizes by heating. When the plasticizer volatilizes, the soft vinyl chloride resin composition is cured. On the other hand, when the carbon number of the alkyl group is C11 or more, the alcohol necessary for the plasticizer ester synthesis is restricted, and as a result, the cost is increased, which is not preferable.

[Insulated wire]
FIG. 1 is a schematic cross-sectional view showing an example of an insulated wire according to the present invention. As shown in FIG. 1, an insulated wire 10 according to the present invention is such that an insulating coating 2 made of the aforementioned soft vinyl chloride resin composition is formed on the outer periphery of a metal conductor wire 1. In FIG. 1, the metal conductor wire 1 is depicted as a single core wire, but a multi-core twisted wire may of course be used. Moreover, there is no special limitation in the manufacturing method of the insulated wire 10, and the conventional method can be utilized.

  The metal conductor wire 1 is not particularly limited, and a gold wire, a silver wire, or the like can be used in addition to a copper wire and an aluminum wire used in a normal insulated wire. Moreover, the conductor which gave metal plating, such as nickel, to the outer periphery of a copper wire may be sufficient. Furthermore, the conductor shape covered with the insulating coating 2 according to the present invention is not particularly limited, and may be a round shape or a quadrilateral shape. The quadrilateral shape in the present invention includes a quadrangular shape with rounded corners and a rounded rectangular shape.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these.

(Production of test materials)
For 100 parts by weight of vinyl chloride resin (PVC) with an average degree of polymerization of 1300, the amount of plasticizer shown in the table (see Tables 1 to 5 described later) and 3 parts by weight of calcium-zinc based lead as a stabilizer Stabilizer and 20 parts by weight of calcium carbonate and 3.5 parts by weight of aluminum silicate as a filler were added and mixed. Thereafter, the mixture was kneaded (roll temperature: 160 ° C., 5 minutes) and pressed (press temperature: 180 ° C., preheated for 3 minutes, pressurized at 10 MPa for 2 minutes) to obtain a thickness of 1 Samples (Comparative Examples 1 to 9 and Examples 1 to 17) of soft vinyl chloride resin compositions were formed into sheet shapes of mm and 2 mm.

(Examination / Evaluation)
For the test materials (Comparative Examples 1 to 9 and Examples 1 to 17) of the soft vinyl chloride resin composition prepared as described above, heat aging resistance test (measurement of residual elongation rate) in accordance with JIS K 6723 A cold resistance test (low temperature embrittlement temperature measurement) and an electrical insulation test (volume resistivity measurement) were performed.

(1) Evaluation of heat aging resistance The residual elongation rate (elongation residual rate) of the test material after heat treatment (100 ° C. atmosphere, 120 hours) relative to the elongation of the test material before heat treatment was calculated. In order to be able to apply to the general insulation coating material of Type 1 No. 1 shown in JIS K 6723 with a margin, the case where the residual elongation is less than 80% is x (failed), and the case where it is 80% or more. It was evaluated as ○ (pass).

(2) Evaluation of cold resistance
In order to be able to apply to the general insulation coating of Type 1 No. 1 shown in JIS K 6723 with a margin, the case where the low temperature embrittlement temperature is higher than -16 ° C is x (failed), and it is -16 ° C or less. The case of was evaluated as ○ (pass).

(3) Electrical insulation evaluation
When the volume resistivity in an atmosphere of 30 ℃ is lower than 10 ¹⁴ Ω · cm so that it can be applied with a margin to the general insulation coating of Type 1 No. 1 shown in JIS K 6723 × (failed) And a case of 10 ¹⁴ Ω · cm or more was evaluated as ○ (pass). The volume resistivity under 60 ° C. atmosphere was lower than 10 ¹³ Ω · cm × a (fail) was evaluated in the case of more than 10 ¹³ Ω · cm ○ and (pass).

(Test and evaluation results)
Tables 1 and 2 show the added plasticizers and test evaluation results in Comparative Examples 1 to 9, and Tables 3 to 5 show the added plasticizers and test evaluation results in Examples 1 to 17, respectively.

(Comparative Example 1)
First, a comparative example will be described with reference to Tables 1 and 2. In Comparative Example 1, 20 parts by mass (per hundred resin: phr) of TOTM (trimellitic acid tri-2-ethylhexyl) as one kind of trimellitic acid ester as a plasticizer with respect to 100 parts by mass of PVC, 30 parts by mass of DIDA (diisodecyl adipate), which is one of aliphatic dibasic acid esters, is added. In Comparative Example 1, the electrical insulation evaluation was unacceptable. This is due to the fact that DIDA has a chain structure (no cyclic structure) and is less susceptible to steric hindrance in PVC. This was thought to be due to the extremely low affinity. In addition, since aliphatic dibasic acid ester had low affinity with PVC, it was difficult to perform homogeneous mixing when added in excess of 30 phr.

(Comparative Examples 2-3)
Comparative Example 2 was obtained by adding 50 phr of TOTM, which is one kind of trimellitic acid ester, as a plasticizer, and Comparative Example 3 was obtained by adding TIDTM (triisodecyl trimellitic acid), which is also one kind of trimellitic acid ester. 50 phr added. Comparative Examples 2 to 3 to which only trimellitic acid ester was added failed in evaluation of cold resistance. As described above, trimellitic acid ester has a high affinity with highly polar PVC because it has a benzene ring and high polarizability. For this reason, it was considered that the interaction with PVC molecules produced a large cohesive force, resulting in low-temperature embrittlement along with PVC.

(Comparative Examples 4-5)
Comparative Example 4 was obtained by adding 50 phr of DOCH (di-2-ethylhexyl 1,2-cyclohexanedicarboxylate), which is a kind of cyclohexanedicarboxylic acid, as a plasticizer. One type of DINCH (diisononyl 1,2-cyclohexanedicarboxylate) added at 50 phr. In Comparative Examples 4 to 5 in which only the cyclohexanedicarboxylic acid ester was added, the electrical insulation evaluation at a high temperature range (60 ° C.) failed. As described above, cyclohexanedicarboxylic acid ester does not have a benzene ring and has a large proportion of nonpolar groups, and therefore has low affinity with highly polar PVC. Therefore, molecular activity becomes active during heating. In addition, since the effect | action which restrict | limits the movement of the carrier in a plasticizer is small, it was thought that evaluation of electrical insulation failed.

  In addition, the addition of DOCH alone (Comparative Example 4) also failed in the evaluation of heat aging resistance. This was thought to be due to the fact that the molecular weight of DOCH was relatively small (molecular weight = 392), and that the amount of volatilization during heating was large.

  As shown in Comparative Examples 2 to 5, the test material to which only one of trimellitic acid ester and cyclohexanedicarboxylic acid ester was added had sufficient characteristics of cold resistance, electrical insulation and heat aging resistance. It was confirmed that it was not satisfied.

(Comparative Examples 6-7)
Comparative Example 6 is obtained by adding 1.2 phr of TOTM, which is one kind of trimellitic acid ester, and 28.8 phr, of DINCH, which is one kind of cyclohexanedicarboxylic acid. In Comparative Example 7, 28.8 phr of TOTM, which is one kind of trimellitic acid ester, and 1.2 phr, which is one kind of cyclohexanedicarboxylic acid, are added. In Comparative Examples 6 to 7, in which the total amount of trimellitic acid ester and cyclohexanedicarboxylic acid was less than 40 parts by mass, the evaluation of heat aging resistance and cold resistance was unacceptable. This was thought to be because the total amount of plasticizer added was less than the amount specified in the present invention, so that a sufficient effect could not be exhibited.

(Comparative Examples 8-9)
Comparative Example 8 is obtained by adding 3.6 phr of TOTM, which is one kind of trimellitic acid ester, and 86.4 phr, of DINCH, which is one kind of cyclohexanedicarboxylic acid. In Comparative Example 9, 86.4 phr of TOTM, which is a kind of trimellitic ester, and 3.6 phr, of DINCH, which is a kind of cyclohexanedicarboxylic acid, are added. In Comparative Examples 8 to 9 in which the total addition amount of trimellitic acid ester and cyclohexanedicarboxylic acid exceeds 80 parts by mass, the evaluation of electrical insulating properties failed. This was thought to be because the volume resistivity as the insulating coating was lowered (that is, the electrical insulation property was lowered) because the total amount of plasticizer added was more than the amount specified in the present invention.

(Examples 1-3)
Next, examples according to the present invention will be described with reference to Tables 3 to 5. In Example 1, 2 phr of TOTM which is one kind of trimellitic acid ester and 48 phr of DINCH which is one kind of cyclohexanedicarboxylic acid ester are added as plasticizers. In Example 2, 20 phr of TOTM and 30 phr of DINCH were added. In Example 3, 48 phr of TOTM and 2 phr of DINCH were added. In all the examples, the evaluations of heat aging resistance, cold resistance and electrical insulation were all acceptable. From the comparison between the results of Examples 1 to 3 and the results of Comparative Examples 2 and 5, the mixing ratio of the first plasticizer (A) and the second plasticizer (B) is at least “4/96 ≦ A / B. A range of ≦ 96/4 ”has been demonstrated to be preferred.

(Examples 4 to 13)
In Examples 4 to 13, in addition to the above Examples 1 to 3, the total addition amount of the first plasticizer and the second plasticizer is fixed to 50 phr, and the first plasticizer and the second plasticizer (That is, the influence of the number of carbon atoms of the first alkyl group and the second alkyl group). The trimellitic acid ester is TOTM (C8), TINTM (1,2,4-benzenetricarboxylic acid triisononyl, C9), TIDTM (C10), and cyclohexanedicarboxylic acid is DOCH (C8), DINCH (C9). , DIDCH (diisodecyl 1,2-cyclohexanedicarboxylate, C10) was used.

  As shown in Examples 4 to 13, in all cases, the evaluations of heat aging resistance, cold resistance and electrical insulation were all acceptable. From the results of Examples 4 to 13 in addition to Examples 1 to 3, the mixing ratio of the first plasticizer (A) and the second plasticizer (B) was “4/96 ≦ A / B ≦ 96/4”. Then, it was demonstrated that the first alkyl group and the second alkyl group can be freely combined in the range of 8 to 10 carbon atoms.

(Examples 14 to 17)
Examples 14-17 investigated the influence of the total addition amount of a 1st plasticizer and a 2nd plasticizer, using TOTM as a 1st plasticizer and using DINCH as a 2nd plasticizer. As shown in Examples 14 to 17, in all cases, the evaluations of heat aging resistance, cold resistance and electrical insulation were all acceptable. From the comparison between the results of Examples 14 to 17 and the results of Comparative Examples 6 to 9 in addition to Examples 1 to 3, the total addition amount of the first plasticizer and the second plasticizer is 40 parts by mass or more 80 A range of less than or equal to parts by weight has been demonstrated to be preferred.

  As described above, it was confirmed that the soft vinyl chloride resin composition according to the present invention does not contain a phthalate ester and has good electrical insulation, cold resistance and heat aging resistance. Furthermore, since a relatively inexpensive compound is used as the plasticizer, the cost can be reduced. Moreover, it can be said that the insulated wire which has the insulation coating which consists of the said soft vinyl chloride resin composition can enjoy those characteristics.

1 ... conductor, 2 ... insulation, 10 ... insulated wire.

Claims (2)

An insulated wire having an insulation coating on the outer periphery of the metal conductor wire,
The insulating coating is a soft vinyl chloride resin composition in which a plasticizer is added to a vinyl chloride resin, and the plasticizer is a first plasticizer made of trimellitic acid ester and a cyclohexanedicarboxylic acid ester. 2 plasticizer, and the mass ratio (A / B) of the first plasticizer (A) and the second plasticizer (B) is 4/96 or more and 96/4 or less, 1 plasticizer (a) and said second plasticizer total amount of (B) (a + B) is, the Ri der 40 parts by mass or more 80 parts by weight with respect to 100 parts by weight of vinyl chloride resin, under 60 ° C. atmosphere insulated wire, wherein the volume resistivity is from the soft matter vinyl chloride resin composition having an electrical insulation property is 10 ¹³ Ω · cm or more. 2. The insulated wire according to claim 1, wherein each of the first alkyl group ester-bonded to the first plasticizer and the second alkyl group ester-bonded to the second plasticizer has 8 or more carbon atoms. An insulated wire characterized by being 10 or less.

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